Appabattys fob



passed .im 1, 1929.

' UNIT-ED STATES PATENT oifiieiaj.v

JOHN B. nalaat, or DETROIT, anonieme.l

APPARATUS FOR HEAT TRE'ATIN G.

Application med February 9,1925. Aseriali no. time.

This invention relates lto heat treating and is herein disclosed asA comprising an' improved method and apparatus -for heat treating magnetic articles to be -liardenedi hy `t quenching.

' Steel, as is 'well known, has certain qualities which are obtained by heating it to dii'- ferent temperatures. and quenching, and the steel, depending on the amount of carbon l0 and other substances in it, has certain critical'temperatiire points. A It is frequently desirable to quench steel articles near the critical temperature to secure 'a desired internal.,

` structurexvand .hardness and at this` temperature steel loses its permeability and becomes non-magnetic.

An object of the inventioniis to provide a -metliod and an apparatus foi: heat treatment ii'i which tlie quenchingtemperature 0 is magnetically controlled. This is accomplished iiifone way by lieatiiig articles in a magnetic field where the articles are. re-

tained b magnetic attraction until they are automatically released for quenching by loss of niagnetisin. Another object is to providean improved eontrelofl articles to be heat treated 'and this is herein accomplished by utilizing the escape of one article from the -licat to control the feed of following articles.

To these ends -and also to improve generally upon the heat treatment-et' magnetic articles, the invention alsoeonsists in the various matters liei'inafter described and claimed.

1n the drawings, Figure 1 is a vertical longitudinal section of an illustrative apparatus,A

Figure 2 is a frontend elevation.

Figure 3 is a rear end elevation. i

The numeral 10 indicates generally a furnace havin y a central heating chamber 12 )referably heated by an electric heating medium in the form of a metallic ribbon 14 helically coiled. The coil also .creates a magnetic field and isenclosed in an insulating cylindrical wall 16 of refractory imiterial held between front and rear'lieads' 18 and 20. Other heatingmeans might be employedand a magnetic field otherwise pro- .duced. `At the front, an inclined chute 22 forms a magazine down which articles A.

`'may roll or slide into a hooked portion 24 whichv lies in alignment with an o ening in the front wall or head v18. A pus er 26 is reciprocated intermittently t'o push the -articles fed into said chamber, said having anA opening, and a coil forming a articles one-by-one into the "heating chainber. The pusher is actuated through an upwardly extending arm 28 on a rock shaft 30, a second arm 32 onthe sha-ft being [convneete'd by alink to the core piece of a solenoid in the casing 36. The solenoid is energized periodicall lby a circuit completed when an artic e is quenched as will later appear. The pusherv 26 is retracted by a coil spring 3 lconnected to. a third arm 40 on t-lierock shaft. i i

Tliearticles Aare vpushed onto a guide or support 42 which may be made from a 4pipe which is cut away atv the top and sides to give the heat accessto the articles. .At a certain place near the rear of the heating chamber, 4 4 thro'iigli which an article will drop when itis heated sufhciently to lose its magnetism.

the guide 42 has a bottom opening The article is li'owe'ver retained niagnetic f.

head 20 by a swinging latch bar The lower end of chute 4G has a kliiiiged gravity.

door 50 removably held iii the rear wall or closure or flap valve 5l which is forced.

open by the falling article andepei'ates a switch plate 56 which establishes electrical' contact between the wires 58 and Gl). lViKre' 58 leads to u binding post. 62 on the housing 36 of the solenoid and wire G0 is electrically connected, tlirough'any suitablesource of current, to a, wire (54 which iu turn leads to' another binding post 66 on said liousing.

Hence, whenever an article escapes from the heating chamber, it controls the mechanism which gives a feeding movement to the following article, and work pieces are thereby fed intermittenly into the chamber with the saine regularity that they leave. it.v Althoiugh the invent-ion has been described by/ reference to certain specific construction and steps, it should be understood, that, in its broader aspects, it is not necessarily limited to the selected illustrations.

I claim:

1. Heat treating apparatus comprising, in combination, a heating chamber, a guide for guide magnetictield opening to retain an 'saidchiainben--and.means 'controlled by the article temporarlly' 'durxnffheating' actuationj'o -sa-id clsureviorcausing the .2. Heat treating apparatus' comprising, 'fin l actuation of'said introducing: means.'

combination, a heatingchamber, a guide'fgr 8.'- .Structure as setfoth in claim 7, 'said' a stream of articles-1n -sa1dchamber,"sa1dl introducing means;including electric motor guide having 4an opening, a chute vleading 'mechanism'f'a'nd said closure controlled ing chamber, and a coil vforrnjiagn'etically re#l said .motor 'mec anism.v

taining anartlcle temporarilyat sald' openl 9.' Apparat-us' for applying heat' treatment lng. v i -j 'vv to artlcles of magneticmaterialcomprising 3. Heat,. treat1ng.apparatus comprising,'1n .a heating chambermeans for conveying arfrom said opening'to the outside'of the heat-` means r incliitlinf a. device for controlling;`

combinatioma heat-ing" ehambe-r, means-for ticles through'. said chamber and discharg- 4 conducting articles through the ehambera ing 'them therefrom, means for 'supplying closure'member-'actuated by said articles, 'articles to said conveying means, means and article':teedinr means 4controlled by the operating magri'etically.4 to retain articles in actuation oi the -c osure member.- said heating chmlbtlllntil they attain a pre- 4. Heat treatingappa 'atus coml'irising, indetermined e'onditimand means actuated lcombination, a heating chamber, a guide in by discharge'of an article from said chamber guide hauling "n opening, a coil for n'iagnetchamber, a closure for the ydischarge end said chamber .for a stream ot' articles, said for controlling sa'id supplyingnicans. i 10, Apparatus'for 4 applying heat treatically Vretatn ng an article-telnporarily at ment to articles of' magnetic material comsaid opening, and 'means actuated by the'r'eprising a. heating chamber, a guideway lease vOtan article for controlling the feed adapted to 'support 'a series of articles in said of the following article: chamber and along,r which sucharticl'es may 5. Heat-treating apparatus comprising," in' be prolielled, .achute positioned to receive combination, a heatingchamber, means .'for articles falling from the end of said guideconductingarticles th'roufzhfthe chambeiz 'a way, and `means `for creating a magnetic field switch -member actuated intermittently by beyond the cnrlof'said guideway and above discharge ot'said articles from said chamber, said:chutclmfhereby an article, after leaving an article magazine, and mechanism conaid guideway,may be magnetically retained trolledfby the switch member for intcrin the heating`-chamber-until the magnetic mittently introducing articles from the mag- Aatti-action .is s uiiiciently Arerhiced to permit azine into the chamber.A the article tofvfall. s

(3.' Heat treating apparatus .comprising a 11. Heat treating. apparatus comprising,

heatingehamber, means for introducing arin'comhination', aheating chamber, an elec-YV ticles intermittently into said eha 1nber,-tric heating elementarranged to produce a means for conducting articles 4through said magnetic field, means for supplying articlesv chamber-and means actuated by the disto' said'. chamberfaiid into said field,.` said 'charge of an article from said chamber for means arranged to-permitldischarge of said causing the actuation of said article intro# artlclesftrom'sald Afield when, by reason of (lacingl means. the heatmg of the article the magnelhc at- "Zf Heatatreating apparatus comprising a traction of the field'therefor becomes' reheating chamber, means' i'or conducting Aarduced ton-predetermined entent. tieles through said chamber, means for in In testimony whereo'I affix my signature. rticles successivel `into sai i' l trod'ucmg' a y --Jomr B. Da .En 

